The present invention relates to a technology for reducing an aged variation of luminance of a display apparatus, and especially, to a technology capable of reducing luminance deterioration due to an aged variation of a pixel fluorescent material of a plasma display, which selectively emits light.
A prior art will be explained using FIG. 4.
FIG. 4 is a block diagram of a conventional display apparatus.
In FIG. 4, 200 is a display apparatus, which is for displaying a video signal that is input from an outside. The display apparatus 200 is constructed of a video signal demodulating section 201, an RGB signal input section 202, an RGB amplification switch section 203, an A/D converter 204R, an A/D converter 204G, an A/D converter 204B, a digital signal processing section 205, and a plasma panel 206.
Next, operation of the above-mentioned conventional display apparatus 200 will be explained.
The video signal demodulating section 201 demodulates a video signal that has been input to an RGB signal, and outputs it to the RGB amplification switch section 203. Also, in case that a video signal is not a video signal, but an RGB signal, the video signal is input to the RGB signal input section 202. And, the RGB signal input section 202 outputs the RGB signal that has been input, to the RGB amplification switch section 203.
The RGB amplification switch section 203 outputs an R signal out of the RGB signal that has been input from the video signal demodulating section 201 or the RGB signal input section 202, to the A/D converter 204R, and outputs a G signal to the A/D converter 204G, and outputs a B signal to the A/D converter 204B.
The A/D converter 204R applies A/D conversion to the R signal that has been input, and outputs it to the digital signal processing section 205. Also, the A/D converter 204G applies A/D conversion to the G signal that has been input, and outputs it to the digital signal processing section 205. And, the A/D converter 204B applies A/D conversion to the B signal that has been input, and outputs it to the digital signal processing section 205.
The digital signal processing section 205 converts and processes each signal that has been input from the A/D converter 204R, the A/D converter 204G and the A/D converter 204B into a signal that the plasma panel 206 can display, and outputs it to the plasma panel 206.
The plasma panel 206 conducts a display by making a fluorescent material radiate based on the signal input from the digital signal processing section 205.
As mentioned above, the plasma display 206 is for conducting a display by using the fluorescent material as luminescence means. Accordingly, like other fluorescent material display elements, luminescence deterioration of a pixel fluorescent material associated with an aged variation occurs between a pixel that is continuously selected for luminescence and a pixel that is not selected. This is recognized as a luminescence difference phenomenon between the pixels. In other words, this phenomenon is caused by a characteristic of a luminescence phenomenon due to an aged variation of a fluorescent material.
Accordingly, conventionally, as a method of avoiding this phenomenon, a study from a material aspect of a fluorescent material and a discharge gas that are used for the plasma display has been conducted. On the other hand, in a circuit used for the plasma display, a method of reducing a luminescence difference by conducting aging by means of all white signals or a method in which the discharge number per unit time period, which participates in luminescence, is reduced, and a time period until an aged variation appears is elongated has been tried.
However, in the method in which a material aspect of the fluorescent material and the discharge gas used for the plasma display is improved, there is a problem that it requires a long study time and a great study expense.
Also, in the method in which the discharge number per unit time period, which participates in luminescence of the plasma display, is reduced, there is a problem that it is hard to see a display.
Also, in case of inverting a video signal that is input to the display apparatus, there is a problem that an inverted signal has to be generated on a side of a device for generating the video signal, when display software of the video signal is generated.